Classic SF author Clarke ( 2001: A Space Odyssey ) walks on well-trodden ground with this entertaining but forgettable book. In the early 22nd century, an enormous asteroid is discovered to be on a collision course with the Earth. Humanity, however, is not unprepared, having become an experienced spacefaring race with outposts throughout the solar system. A spaceship, the Goliath , built decades earlier for just such an emergency, is dispatched to deflect the asteroid from its apocalyptic rendezvous. But the mission goes awry, leaving Captain Robert Singh and his crew to find a way to to save the Earth. Clarke writes with dramatic flair, cutting between past and future with dizzying frequency. Nonetheless, the book fails to convey the tension of the situation he has set up. Clarke describes the setting and background with such loving detail that the asteroid seems almost an afterthought, creating a rush of action in the last quarter of the narrative. The characterizations, save for that of Singh, are fairly thin, and Clark's wit occasionally gives the prose a jarring, unintentionally satiric flavor. While this is a fast read, it is not a particularly impressive one. (June)